Porcelain root tooth



Dec. 6, 1932. E. P- SHAW. 1,890,132

PORCELAIN ROOT TOOTH Original Filed Aug. 3, 1922 Patented Dec. 6, 1932 UNITED STATES PATENT OFFICE ERNEST P. SHAWN, OF SAN ANTONIO, TEXA$, .ASSIGNOR TO THE COLUMBUS DENTAL MANUFACTURING COMPANY, OF COLUMBUS, OHIO, A CORPORATION OF OHIO PORCELAIN ROOT TOOTH Continuation of application Serial No. 579,281, filed August 3, 1922. This application filed June 7, 1927. Serial No. 197,126,

Porcelain root work has attracted more attention than any recent development in prosthetic dentistry. This is called porcelain root, or cone work because the dummies are constructed by tapering the tooth from the gingival third toward the gum; each dummy being made to reproduce the tooth form normal to each individual mouth. This gives the efiect and appearance of a natural root which comes in contact with the soft tissue.

These porcelain roots must be highly glazed and when placed in the sockets of recent ex traction, or in surgically prepared sockets, or to rest against the gum, they are accepted by a steadily increasing number of dentists as the only practical and aesthetic method for fixed bridgework.

The non-irritating quality of porcelain has long been recognized in the field of dentistry. The mucous membrane of tie mouth takes very kindly to porcelain, and, although a foreign body generally produces an irritation, I find the minimum amount of irritation present with porcelain. This important characteristic makes artificial root insertion possible.

One problem which has confronted me is to prevent the excessive absorption following the extraction of an anterior tooth. This absorption is very objectionable for two reasons:

First, when a bridge is constructed to supply the missing tooth, the dummy facing must be placed higher than the crown of the original tooth to compensate for the absorption. This breaks the uniformity of the gingival lines.

Secondly, there is always a pocket or depression produced on the lingual of the dummy facing, where food will collect in spite of all precautions to the contrary. If this absorption is counteracted, I will have produced a piece of work which is pleasing to the eye and sanitary in construction. If this is done by the porcelain root insertion, the re sults produced will be pleasing both to the operator and patient. Practically all of the absorption is prevented, and, as there is nothing but porcelain in contact with the tissues in the bridged space, the irritation is reduced to the least possible amount and the patient is given a greater chance for the maintenance of a clean and healthy mouth.

What is known to the dental profession as pin facing technic has many disadvantages among which may be noted tnat the pin tooth has no standard porcelain certainties on which to construct metal attachments due to the shrinkage and warpage of the porcelain during the baking process. Again during the baking shift, the pins change their relative positions in the tooth, and for these reasons, the pin tooth is very hard to replace even when the facing is used Without the root portion.

To repair pin facing cases, the dentist usually finds it necessary to romove the bridge from the mouth, and replace the dummy or supply with a new structure. Different methods of repair have been advanced, but none have fully filled the requirements of the profession, and usually the conscientious clentist removes the bridge to make the repair.

lVhen the pin facing is employed in the anterior region, the pins often extend 7 through the lingual cast gold restoration. When the facing is cemented to place, and the pins cut flush with the cast gold surface, there is a decided tendency for the cement to Wash out and allow the facing to become loosened. 30 Loosening of the teeth is encouraged by food striking the end of the pins during the act of incising. If the pins are cut short enough to permit the gold to completely cover the ends of the pins, they are often too short to 35 support and anchor the facing.

Among the primary advantages of my invention may be mentioned the following:

By means of my invention the facing may have all of the surfaces that come in contact with the metal backlng readily ground to standards of dimension.

Generically the object of my invention is to provide an interchangeable artificial porcelain root tooth, and a backing therefor, said tooth and backing to function as a dummy or supply. The porcelain root to be inserted in the tooth socket (alveolus) where a natural tooth has been recently extracted, or to be placed in contact with the edentulous add porcelain to other typesofartificial teeth portion of the ridge, the soft tissues and mucous membrane having closed and healed over the tooth socket.

Hitherto the dentist has been obllged to a as sold by the manufacturer to produce a porcelain root tooth. The dentist found 'it ec a y ave an pen equ pmentat gether with extraordinary skill to man pulate the porcelain from its finely ground state until its final bake or glaze upon the artificial.

tooth. It was necessary to have the patient present throughout the whole'baking process or take with difficulty a large number of accurate impressions, either of which consumed muchtime. In theeventthat breakage occurred,it was necessary to remove the bridge from the mouth and construct and substitute a new dummy for the broken member.

These disadvantagesare overcomewith the artificial porcelain root toothandmetal backing therefor, the latter having a post and rib.

Further, the dentist can grind the artificial procelain root to the requireddimensions and contour then by adding, a thin veneer of. lower fusing porcelain to the ground root and.

glazing he can procure ideal results hastily and accurately. In the event the dentist does notown the necessary equipmentforbaking on the veneer .he can send the tooth to the laboratory and have the workfdonefor him hequ l y. qdr llltS- A further obj ect of my invention is'to re duce theamount of time needed either forthe.

dentist or the patient andgalso reduce the number of impressions.

A further object of my invention is to pro- [0 vide a porcelain "tooth in whichthe surfaces of the ee a Corrie Hmnt Qt w h the backingare ground to a standard of dimension allowingfo'r interchangeability and re-; M placeability'in the event of breakage".

Tn the drawing;

Figure l is a side elevation of a porcelain root tooth, with backing attached thereto, embodying my invention.

Figure 2 is a perspective view of a backing 5H6 embodying my invention, detached from the tooth.

Figure 3 is a rear orlingualperspectiVe view of my improved tooth looking fromthe incisal edge to the base of .thetooth.

proved backing With a still further modified 0st. p Figure 9 is a side elevation of the tooth divided by dotted lines into the root portion 4,. the lingual portion 3 and the labial or facing portion 1a.

It'will' be understood that my invention is; applicable to both; anterior and posterior teeth; V I

As will be seen from the drawing, my improveditoothi has two fiat planes designated by the reference numerals 1 and 2, which intersect preferably in an--obtuse--angle.- The plane l is a fiat plane formed on the labial or facing, portion 1aof the tooth and extending the full width of the tooth .in one dimension,- and 'fromthe incisal edge of the tooth to its inter section-with the root plane or gingival plane .or base 2. The gingivalplane2 isa flat plane extending the full" width of f; the tooth in one dimension, and

from its intersection with'the plane 1 to and intersecting with the curved lingual surface of the lingual portion 8 of the porcelain root l, whereby substantially the lingual half, of the'root4 constitutes an overhanging por tion at the base of the tooth as perhaps more fully illustrated in Figures 1 and 5; the plane 2'being directed upwardly lingually'and as shown in these two figures. This gingival base plane 2'is provided with 'a slot ,5 :ex-7,

tending throughout the length of the plane and opening to said plane a post hole 6, which post holeis parallel to the face of the gingiyal;

plane 2 as clearly shown in' Figure l in dotted lines, is extended at its inner end,la'bially beyond the face-of the plane 1.

' The labial or buccal boundary or-wal-lof the slot is preferably in the plane .and con tinuousof the plane 1, as shown in the drawing, the slot 5 communicates throughoutits entire longitudinal dimension gingivally with theposthole 6.1 i i The post hole 6 is preferably cylindrically shaped and of-one diameter and extends-from the lingual surface of theroot 4 buccallyior' labially and downwardly, being parallel, asabove stated, with the gingiv'al'or root base 2, to -a point within the structure of the tooth which point is buccal or labial to theplane '1 as clearly. shown in the drawing.

The backing shown in the several-figures of= the drawing'presents a fiat attachment portion 7 "which engages with the tooth and is-complemental to and is engaged with the gingival erroot plane 2, said portion being provided with a downwardly extending wing 8 disposed .atan obtuse; angle to the portion 7 and complemental with the surface 1 of the tooth when the backing and tooth "are enese Extending gingi-vally from i the attaching portion-7 is a rib9'surmounted by a post 10, the post being of-a greater diameter than the llb 9, s'aid 'post being parallel with the attaching portion 7 of the backing and extending longitudinally of the portion 7 This post extends labially or buccally as at 10a beyond the wing 8, and is complemental with the post opening 6, in the tooth, the rib 9 being complemental with the slot 5 of the tooth. This post and rib may be secured in any desired manner to the backing.

As shown in Figures 6 and 7, the post at its labial or buccal end may be flattened as at 11. Again, the post may be tapered as shown in Figure 8, the post in this figure being designated by the reference numeral 12, the greatest diameter of the tapered post 12 being at its lingual end. In Figure 5, I have shown my improved porcelain root tooth provided with a saddle 13 at its gingival end, which saddle is designed to rest on or against the soft tissue of the ridge. lVhile this saddle is shown in connection with a bicuspid, it will be understood that the saddle effect may be formed in any of the teeth.

I have shown associated with the bicuspid in Figure 5, the cast gold 14, which provides a masticating surface of gold, this cast being secured in the well known manner to the backing shown in the drawing, and heretofore described, the rib 9 and post 10 only showing in this figure.

From the above it will be seen from a broad aspect that my invention provides an artificial tooth comprising the porcelain root body portion and an overhang portion, said overhang portion extending rearwardly or lingually from the facing or body portion, and which overhang portion is provided in its under face with an under cut recess extending gingivally, and further my invention is provided with a backing complemental with the tooth of this structure.

The words labial and facing are used in the specification and claim as synonyms.

A preferred method of making the artificial tooth hereinbefore described consists in assembling separate lingual labial and root portions and uniting them into an integral structure. A part which, in the finished tooth will be the lingual portion 3, may be placed on a backing such as shown in Figs. 2 or 6. lVi-th this part thus positioned, the rinding or cutting of a plane surface as a parallel continuation of the plane surface 8 may be effected with the greatest ease and precision. The plane surface thus cut or ground is indicated in the finished tooth shown in Fig. 9 by the vertical dotted line. This surface is placed in contact with the fiat side of the labial portion 1a, and the obtuse angle formed by the surfaces 1 and 2 is thus, in accordance with the grinding of the lingual portion, made in advance to agree with the angularity of the wings 7 and 8. Prior to the assemblin of the two portions, a notch may be cut in the sides of the lingual portion adjacent the plane surface formed as above indicated. Then when the two parts are assembled and held in place (for instance by means of wax applied at the place where, in the finished structure shown in Fig. 9 the root portion is indicated), the notches are filled with a mix of porcelain, and the assembly is baked. The baking results in firmly attaching the two portions to each other, the mix of porcelain having fused and having become practically integral with the portions 1a and 3. The wax having been melted away during the baking, a mix of porcelain is applied at the top of thetwo portions thus united, being shaped as desired and the tooth being again baked. The assembly is then ground to shape and glazed. If desired, the root portion 4 may be built up only to a height as shown in Fig. 5 and then baker. If afterwards, a conical root is desired, a second mix of porcelain may be applied to the saddle 13 and the application baked.

This application is filed as a continuation of the application of Shaw and Robinson, filed August 3, 1922, Serial N 0. 579,381.

What I claim is:

A plate type backing for an artificial pontic tooth, said tooth having a root extension and having in its occlusally directed end surface an undercut socket comprising a slot tenninating away from said surface in a broadened recess, said backing consisting of a top designed to engage the base of the root ex tension, a depending front intersecting said top in an angle and adapted to engage the lingual face of the tooth, a tenon extending longitudinally of and upward from said top, and at one end extending labially beyond the labial edge of said top, and adapted to en'- gage said socket.

In testimony whereof I affix my signature.

ERNEST P. SHAW. 

